Data as of Sep 13, 2026. Both funds on the fields they both publish, from the same sources.
MDY vs VOO: how they differ
MDY and VOO hold 0% of their weight in the same names, and VOO returned more over the year.
SPDR S&P MidCap 400 ETF Trust and Vanguard 500 Index Fund.
What they hold in common
By the books each fund has filed, MDY and VOO hold 0% of their money in the same securities at the same weight.
| Only in MDY | Only in VOO |
|---|---|
| Twilio Inc. Class A 1.00% | NVIDIA Corp 7.53% |
| Illumina Inc. 0.86% | Apple Inc 6.61% |
| TechnipFMC plc 0.86% | Microsoft Corp 4.31% |
| Everpure Inc. Class A 0.84% | Amazon.com Inc 3.63% |
| Okta Inc. Class A 0.81% | Alphabet Inc 3.26% |
| U.S. Dollar 0.80% | Broadcom Inc 2.78% |
| ATI Inc 0.77% | Alphabet Inc 2.60% |
| nVent Electric plc 0.71% | Micron Technology Inc 2.02% |
Weight overlap is an ETFIQ calculation: for every security both funds hold, the smaller of the two weights, summed. Above 50%, holding both is close to holding one of them twice. Holdings dated Jun 30, 2026 and Sep 10, 2026.
| MDY SPDR S&P MidCap 400 ETF Trust | VOO Vanguard 500 Index Fund | |
|---|---|---|
| Where it sits | Core index fund | Core index fund |
| Issuer | State Street | Vanguard |
| What it is | S&P MidCap 400 | S&P 500 |
| Total return, 1 year | +13.0% | +17.6% |
| S&P 500 over the same days | +17.5% | +17.5% |
| Gap to the S&P 500 | −4.5 pts | +0.1 pts |
| Expense ratio | 0.23% | 0.03% |
| Already in the S&P 500 | 0.0% | 100.0% |
| Holdings | 401 | 506 |
MDY in plain words
MDY is an index equity fund tracking the S&P MidCap 400. Over the year to Sep 11, 2026 it returned +13.0% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.23% a year. By its holdings filed for Sep 10, 2026, 0% of the fund by weight is stocks the S&P 500 also holds, across 401 positions, with the top ten at 7.9%. It sat 5.3% below its high of Aug 14, 2026 on Sep 11, 2026.
VOO in plain words
VOO is an index equity fund tracking the S&P 500. Over the year to Sep 11, 2026 it returned +17.6% with distributions reinvested, against +17.5% for the S&P 500 and +23.0% for the Nasdaq-100. The prospectus expense ratio is 0.03% a year. By its holdings filed for Jun 30, 2026, 100% of the fund by weight is stocks the S&P 500 also holds, across 506 positions, with the top ten at 36.5%.
Questions people ask
- Which returned more over the last year, MDY or VOO?
- In the year to Sep 13, 2026, with distributions reinvested, MDY returned +13.0% and VOO returned +17.6%, so VOO returned more. One year is one year; the longer windows are in the table.
- Which is cheaper, MDY or VOO?
- MDY charges 0.23% a year and VOO charges 0.03%, so VOO is cheaper. Fees come from each fund's prospectus.
- How much do MDY and VOO overlap with the S&P 500?
- By their latest filed holdings, 0% of MDY and 100% of VOO by weight is stocks the S&P 500 already holds. Between the two funds, 0% of their books are the same securities at the same weight.
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Where these figures came from
ETFIQ links to the documents behind every figure. It is not affiliated with any issuer, and a link is not an endorsement.
Cite this page. ETFIQ, MDY against VOO, data as of Sep 13, 2026. https://etfiq.com/compare/any/mdy-vs-voo Free to use with attribution; the underlying files are at Open data.
A comparison is not a recommendation. Standards and sources